Fibrous structures exhibiting improved wet compression properties and methods for making same

ABSTRACT

Fibrous structures that exhibit improved wet compression properties, and more particularly to wet compression-enhancing agent-containing fibrous structures that provide superior wet compression properties compared to the same fibrous structures without the wet compression-enhancing agent, are provided.

FIELD OF THE INVENTION

The present invention relates to fibrous structures that exhibitimproved wet compression properties, and more particularly to wetcompression-enhancing agent-containing fibrous structures that providesuperior wet compression properties compared to the same fibrousstructures without the wet compression-enhancing agent.

BACKGROUND OF THE INVENTION

Fibrous structures comprising polymers such as polyacrylamide and/orpolyacrylamide containing polymers and such as absorbent gel materials,for example crosslinked acrylic acid particles, are known in the art.

In light of the foregoing, it is clear that there has existed a longfelt, unmet need for a fibrous structure, more particularly a dryfibrous structure that exhibits superior wet compression propertiescompared to the same fibrous structure without the wetcompression-enhancing agent.

Accordingly, there is a need for a fibrous structure comprising a wetcompression-enhancing agent such that the fibrous structure exhibitssuperior wet compression properties compared to the same fibrousstructure without the wet compression-enhancing agent.

SUMMARY OF THE INVENTION

The present invention fulfills the needs described above by providing afibrous structure, for example a dry paper towel that exhibits superiorwet compression properties compared to the same fibrous structurewithout the wet compression-enhancing agent.

In one example of the present invention, a fibrous structure comprisinga wet compression-enhancing agent such that the fibrous structureexhibits at least one of the following properties:

a. at least one Wet Compression value in a load value range of from 100g to 300 g during the Compression Portion of the Wet Compression TestMethod that is statistically greater than the corresponding WetCompression value of the same fibrous structure void of the wetcompression-enhancing agent as measured according to the Wet CompressionTest Method; and

b. at least one Wet Compression value in a load value range of from 50 gto 300 g during the Relaxation Portion of the Wet Compression TestMethod that is statistically greater than the corresponding WetCompression value of the same fibrous structure void of the wetcompression-enhancing agent as measured according to the Wet CompressionTest Method.

Accordingly, the present invention provides wet compression-enhancingagent containing fibrous structures that exhibit superior wetcompression properties compared to known fibrous structures void of suchwet compression-enhancing agent(s) and methods for making such fibrousstructures.

DETAILED DESCRIPTION OF THE INVENTION Definitions

“Fibrous structure” as used herein means a structure that comprises oneor more fibrous filaments and/or fibers. In one example, a fibrousstructure according to the present invention means an orderlyarrangement of filaments and/or fibers within a structure in order toperform a function. Non-limiting examples of fibrous structures of thepresent invention include paper, fabrics (including woven, knitted, andnon-woven), and absorbent pads (for example for diapers or femininehygiene products).

Non-limiting examples of processes for making fibrous structures includeknown wet-laid processes, such as wet-laid papermaking processes, andair-laid processes, such as air-laid papermaking processes. Wet-laidand/or air-laid papermaking processes and/or air-laid papermakingprocesses typically include a step of preparing a composition comprisinga plurality of fibers that are suspended in a medium, either wet, morespecifically aqueous medium, or dry, more specifically gaseous medium,such as air. The aqueous medium used for wet-laid processes isoftentimes referred to as a fiber slurry. The fiber composition is thenused to deposit a plurality of fibers onto a forming wire or belt suchthat an embryonic fibrous structure is formed, after which drying and/orbonding the fibers together results in a fibrous structure. Furtherprocessing the fibrous structure may be carried out such that a finishedfibrous structure is formed. For example, in typical papermakingprocesses, the finished fibrous structure is the fibrous structure thatis wound on the reel at the end of papermaking, and may subsequently beconverted into a finished product, e.g. a sanitary tissue product.

Another process that can be used to produce the fibrous structures is amelt-blowing and/or spunbonding process where a polymer composition isspun into filaments and collected on a belt to produce a fibrousstructure. In one example, a plurality of fibers may be mixed with thefilaments prior to collecting on the belt and/or a plurality of fibersmay be deposited on a prior produced fibrous structure comprisingfilaments.

The fibrous structures of the present invention may be homogeneous ormay be layered in the direction normal to the machine direction. Iflayered, the fibrous structures may comprise at least two and/or atleast three and/or at least four and/or at least five layers.

The fibrous structures of the present invention may be co-formed fibrousstructures. “Co-formed” as used herein means that the fibrous structurecomprises a mixture of at least two different components wherein atleast one of the components comprises a filament, such as apolypropylene filament, and at least one other component, different fromthe first component, comprises a solid additive, such as a fiber and/ora particulate. In one example, a co-formed fibrous structure comprisessolid additives, such as fibers, such as wood pulp fibers and/orabsorbent gel articles of manufacture and/or filler particles and/orparticulate spot bonding powders and/or clays, and filaments, such aspolypropylene filaments.

“Solid additive” as used herein means a fiber and/or a particulate.

“Particulate” as used herein means a granular substance or powder.

“Fiber” and/or “Filament” as used herein means an elongate particulatehaving an apparent length greatly exceeding its apparent width, i.e. alength to diameter ratio of at least about 10. In one example, a “fiber”is an elongate particulate as described above that exhibits a length ofless than 5.08 cm (2 in.) and a “filament” is an elongate particulate asdescribed above that exhibits a length of greater than or equal to 5.08cm (2 in.).

Fibers are typically considered discontinuous in nature. Non-limitingexamples of fibers include wood pulp fibers and synthetic staple fiberssuch as polyester fibers.

Filaments are typically considered continuous or substantiallycontinuous in nature. Filaments are relatively longer than fibers.Non-limiting examples of filaments include meltblown and/or spunbondfilaments. Non-limiting examples of articles of manufacture that can bespun into filaments include natural polymers, such as starch, starchderivatives, cellulose and cellulose derivatives, hemicellulose,hemicellulose derivatives, and synthetic polymers including, but notlimited to polyvinyl alcohol filaments and/or polyvinyl alcoholderivative filaments, and thermoplastic polymer filaments, such aspolyesters, nylons, polyolefins such as polypropylene filaments,polyethylene filaments, and biodegradable or compostable thermoplasticfibers such as polylactic acid filaments, polyhydroxyalkanoate filamentsand polycaprolactone filaments. The filaments may be monocomponent ormulticomponent, such as bicomponent filaments.

In one example of the present invention, “fiber” refers to papermakingfibers. Papermaking fibers useful in the present invention includecellulosic fibers commonly known as wood pulp fibers. Applicable woodpulps include chemical pulps, such as Kraft, sulfite, and sulfate pulps,as well as mechanical pulps including, for example, groundwood,thermomechanical pulp and chemically modified thermomechanical pulp.Chemical pulps, however, may be preferred since they impart a superiortactile sense of softness to tissue sheets made therefrom. Pulps derivedfrom both deciduous trees (hereinafter, also referred to as “hardwood”)and coniferous trees (hereinafter, also referred to as “softwood”) maybe utilized. The hardwood and softwood fibers can be blended, oralternatively, can be deposited in layers to provide a stratified web.Also applicable to the present invention are fibers derived fromrecycled paper, which may contain any or all of the above categories aswell as other non-fibrous articles of manufacture such as fillers andadhesives used to facilitate the original papermaking.

In addition to the various wood pulp fibers, other cellulosic fiberssuch as cotton linters, rayon, lyocell and bagasse can be used in thisinvention. Other sources of cellulose in the form of fibers or capableof being spun into fibers include grasses and grain sources.

“Dry fibrous structure” as used herein means a fibrous structure thatcomprises less than 30% and/or less than 20% and/or less than 15% and/orless than 10% and/or less than 7% and/or less than 5% and/or less than3% and/or less than 2% and/or less than 1% and/or less than 0.5% byweight of moisture based on the fibrous structure as measured accordingto the Moisture Content Test Method described herein.

“Sanitary tissue product” as used herein means a soft, low density (i.e.<about 0.15 g/cm³) web useful as a wiping implement for post-urinary andpost-bowel movement cleaning (toilet tissue), for otorhinolaryngologicaldischarges (facial tissue), multi-functional absorbent and cleaning uses(absorbent towels), and folded sanitary tissue products such as napkinsand/or facial tissues including folded sanitary tissue productsdispensed from a container, such as a box. The sanitary tissue productmay be convolutedly wound upon itself about a core or without a core toform a sanitary tissue product roll.

In one example, the sanitary tissue product of the present inventioncomprises a fibrous structure according to the present invention.

The sanitary tissue products of the present invention may exhibit abasis weight between about 10 g/m² to about 120 g/m² and/or from about15 g/m² to about 110 g/m² and/or from about 20 g/m² to about 100 g/m²and/or from about 30 to 90 g/m². In addition, the sanitary tissueproduct of the present invention may exhibit a basis weight betweenabout 40 g/m² to about 120 g/m² and/or from about 50 g/m² to about 110g/m² and/or from about 55 g/m² to about 105 g/m² and/or from about 60 to100 g/m².

The sanitary tissue products of the present invention may exhibit atotal dry tensile strength of at least 59 g/cm (150 g/in) and/or fromabout 78 g/cm (200 g/in) to about 394 g/cm (1000 g/in) and/or from about98 g/cm (250 g/in) to about 335 g/cm (850 g/in). In addition, thesanitary tissue product of the present invention may exhibit a total drytensile strength of at least 196 g/cm (500 g/in) and/or from about 196g/cm (500 g/in) to about 394 g/cm (1000 g/in) and/or from about 216 g/cm(550 g/in) to about 335 g/cm (850 g/in) and/or from about 236 g/cm (600g/in) to about 315 g/cm (800 g/in). In one example, the sanitary tissueproduct exhibits a total dry tensile strength of less than about 394g/cm (1000 g/in) and/or less than about 335 g/cm (850 g/in). In anotherexample, the sanitary tissue products of the present invention mayexhibit a total dry tensile strength of at least 196 g/cm (500 g/in)and/or at least 236 g/cm (600 g/in) and/or at least 276 g/cm (700 g/in)and/or at least 315 g/cm (800 g/in) and/or at least 354 g/cm (900 g/in)and/or at least 394 g/cm (1000 g/in) and/or from about 315 g/cm (800g/in) to about 1968 g/cm (5000 g/in) and/or from about 354 g/cm (900g/in) to about 1181 g/cm (3000 g/in) and/or from about 354 g/cm (900g/in) to about 984 g/cm (2500 g/in) and/or from about 394 g/cm (1000g/in) to about 787 g/cm (2000 g/in).

The sanitary tissue products of the present invention may exhibit aninitial total wet tensile strength of at least 118 g/cm (300 g/in)and/or at least 157 g/cm (400 g/in) and/or at least 196 g/cm (500 g/in)and/or at least 236 g/cm (600 g/in) and/or at least 276 g/cm (700 g/in)and/or at least 315 g/cm (800 g/in) and/or at least 354 g/cm (900 g/in)and/or at least 394 g/cm (1000 g/in) and/or from about 118 g/cm (300g/in) to about 1968 g/cm (5000 g/in) and/or from about 157 g/cm (400g/in) to about 1181 g/cm (3000 g/in) and/or from about 196 g/cm (500g/in) to about 984 g/cm (2500 g/in) and/or from about 196 g/cm (500g/in) to about 787 g/cm (2000 g/in) and/or from about 196 g/cm (500g/in) to about 591 g/cm (1500 g/in).

In another example, the sanitary tissue products of the presentinvention may exhibit an initial total wet tensile strength of less thanabout 78 g/cm (200 g/in) and/or less than about 59 g/cm (150 g/in)and/or less than about 39 g/cm (100 g/in) and/or less than about 29 g/cm(75 g/in).

The sanitary tissue products of the present invention may exhibit adensity (measured at 95 g/in²) of less than about 0.60 g/cm³ and/or lessthan about 0.30 g/cm³ and/or less than about 0.20 g/cm³ and/or less thanabout 0.10 g/cm³ and/or less than about 0.07 g/cm³ and/or less thanabout 0.05 g/cm³ and/or from about 0.01 g/cm³ to about 0.20 g/cm³ and/orfrom about 0.02 g/cm³ to about 0.10 g/cm³.

The sanitary tissue products of the present invention may be in the formof sanitary tissue product rolls. Such sanitary tissue product rolls maycomprise a plurality of connected, but perforated sheets of fibrousstructure, that are separably dispensable from adjacent sheets. In oneexample, one or more ends of the roll of sanitary tissue product maycomprise an adhesive and/or dry strength agent to mitigate the loss offibers, especially wood pulp fibers from the ends of the roll ofsanitary tissue product.

The sanitary tissue products of the present invention may comprisesadditives such as softening agents, temporary wet strength agents,permanent wet strength agents, bulk softening agents, lotions,silicones, wetting agents, latexes, especially surface-pattern-appliedlatexes, dry strength agents such as carboxymethylcellulose and starch,and other types of additives suitable for inclusion in and/or onsanitary tissue products.

“Weight average molecular weight” as used herein means the weightaverage molecular weight M_(w) (in units of g/mol) as determined usinggel permeation chromatography according to the protocol found inColloids and Surfaces A. Physico Chemical & Engineering Aspects, Vol.162, 2000, pg. 107-121.

“Number average molecular weight” as used herein means the numberaverage molecular weight M_(n) (in units of g/mol) as determined usinggel permeation chromatography according to the protocol found inColloids and Surfaces A. Physico Chemical & Engineering Aspects, Vol.162, 2000, pg. 107-121.

“Basis Weight” as used herein is the weight per unit area of a samplereported in lbs/3000 ft² or g/m² and is measured according to the BasisWeight Test Method described herein.

“By weight of moisture” or “moisture content” means the amount ofmoisture present in a fibrous structure measured according to theMoisture Content Test Method described herein immediately after thefibrous structure has been conditioned in a conditioned room at atemperature of 73° F.±4° F. (about 23° C.±2.2° C.) and a relativehumidity of 50%±10% for 2 hours.

“Machine Direction” or “MD” as used herein means the direction parallelto the flow of The fibrous structure through The fibrous structuremaking machine and/or sanitary tissue product manufacturing equipment.

“Cross Machine Direction” or “CD” as used herein means the directionparallel to the width of The fibrous structure making machine and/orsanitary tissue product manufacturing equipment and perpendicular to themachine direction.

“Ply” as used herein means an individual, integral fibrous structure.

“Plies” as used herein means two or more individual, integral fibrousstructures disposed in a substantially contiguous, face-to-facerelationship with one another, forming a multi-ply fibrous structureand/or multi-ply sanitary tissue product. It is also contemplated thatan individual, integral fibrous structure can effectively form amulti-ply fibrous structure, for example, by being folded on itself.

“Water-soluble material” as used herein means a material that ismiscible in water. In other words, a material that is capable of forminga stable (does not separate for greater than 5 minutes after forming thehomogeneous solution) homogeneous solution with water at ambientconditions.

“Retained” as used herein with respect to a wet compression-enhancingagent being retained by a fibrous structure means that the wetcompression-enhancing agent does not become disassociated from a fibrousstructure comprising the wet compression-enhancing agent under normaluse conditions. In one example, the wet compression-enhancing agent doesnot become disassociated from a fibrous structure comprising the wetcompression-enhancing agent containing the wet compression-enhancingagent under normal use conditions after the fibrous structure issaturated with distilled water.

Fibrous Structure

A non-limiting example of a fibrous structure of the present inventionmay be a dry fibrous structure, such as a dry paper towel.

In one example, the fibrous structure comprises two or more wetcompression-enhancing agents. In another example, the fibrous structurecomprises a blend (mixture) of two or more wet compression-enhancingagents. In another example, the two or more wet compression-enhancingagents are different wet compression-enhancing agents.

In one example, the fibrous structure comprises a web. In anotherexample, the fibrous structure comprises a particle.

The fibrous structure of the present invention may comprise a pluralityof pulp fibers. Further, the fibrous structure of the present inventionmay comprise a single-ply or multi-ply sanitary tissue product, such asa paper towel.

The fibrous structure of the present invention may comprise a wetcompression-enhancing agent. When present, the wet compression-enhancingagent(s) may be present in and/or on the fibrous structure at a level ofgreater than 0.005% and/or greater than 0.01% and/or greater than 0.05%and/or greater than 0.1% and/or greater than 0.15% and/or greater than0.2% and/or less than 5% and/or less than 3% and/or less than 2% and/orless than 1% by weight of the fibrous structure. In one example, the wetcompression-enhancing agent is present in and/or on the fibrousstructure at a level of from about 0.005% to about 1% by weight of thefibrous structure.

In another example of the present invention, a fibrous structure maycomprise a wet compression-enhancing agent at a level of from greaterthan 0 pounds/ton (#/ton) and/or greater than 0.1#/ton and/or greaterthan 0.5#/ton and/or greater than 1#/ton and/or greater than 2#/tonand/or greater than 3 #/ton and/or to less than 20 #/ton and/or to lessthan 15 #/ton and/or to less than 10 #/ton and/or to less than 6 #/tonand/or to 5 #/ton or less and/or to 4 #/ton or less by weight of thefibrous structure. The level of wet compression-enhancing agent presentin and/or on a fibrous structure as used herein according to the presentinvention is in terms of active solids basis of the wetcompression-enhancing agent.

The fibrous structure may comprise other ingredients in addition to thewet compression-enhancing agent, for example a surfactant. Thesurfactant may be present in the fibrous structure at a level of fromabout 0.01% to about 0.5% by weight of the fibrous structure.Non-limiting examples of a suitable surfactant include C₈₋₁₆ alkylpolyglucoside, cocoamido propyl sulfobetaine or mixtures thereof.

In another example, the wet compression-enhancing agent may be presentin and/or on a fibrous structure in a pattern, such as a non-randomrepeating pattern composing lines and or letters/words, and/or presentin and/or on regions of different density, different basis weight,different elevation and/or different texture of the fibrous structure.In one example, the wet compression-enhancing agent may be present inand/or on a fibrous structure in a pattern such that is it phasedregistered with embossments on the fibrous structure, perforations inthe fibrous structure, wet molded texture in the fibrous structure,and/or printing on the fibrous structure.

In another example, the fibrous structure of the present inventionexhibits at least one Wet Compression value in a load value range offrom 100 g to 300 g during the Compression Portion of the WetCompression Test Method that is statistically greater than thecorresponding Wet Compression value of the same fibrous structure voidof the wet compression-enhancing agent as measured according to the WetCompression Test Method. In another example, the fibrous structure ofthe present invention exhibits at least one Wet Compression value in theload value range of from 100 g to 300 g during the Compression Portionof the Wet Compression Test Method that is greater than thecorresponding Wet Compression value of the same fibrous structure voidof the wet compression-enhancing agent by at least 0.010 mm as measuredaccording to the Wet Compression Test Method. In still another example,the fibrous structure of the present invention exhibits at least one WetCompression value in the load value range of from 100 g to 300 g duringthe Compression Portion of the Wet Compression Test Method that isgreater than the corresponding Wet Compression value of the same fibrousstructure void of the wet compression-enhancing agent by at least 0.012mm as measured according to the Wet Compression Test Method. In evenanother example, the fibrous structure of the present invention exhibitsat least one Wet Compression value in the load value range of from 100 gto 300 g during the Compression Portion of the Wet Compression TestMethod that is greater than the corresponding Wet Compression value ofthe same fibrous structure void of the wet compression-enhancing agentby at least 0.014 mm as measured according to the Wet Compression TestMethod described herein.

In another example, the fibrous structure of the present inventionexhibits a Wet Compression value of greater than 0.446 mm at a loadvalue of 300 g during the Compression Portion of the Wet CompressionTest Method and/or a Wet Compression value of greater than 0.543 mm at aload value of 200 g during the Compression Portion of the WetCompression Test Method and/or a Wet Compression value of greater than0.622 mm at a load value of 150 g during the Compression Portion of theWet Compression Test Method and/or a Wet Compression value of greaterthan 0.676 mm at a load value of 125 g during the Compression Portion ofthe Wet Compression Test Method and/or a Wet Compression value ofgreater than 0.742 mm at a load value of 100 g during the CompressionPortion of the Wet Compression Test Method and/or a Wet Compressionvalue of greater than 0.824 mm at a load value of 75 g during theCompression Portion of the Wet Compression Test Method and/or a WetCompression value of greater than 0.923 mm at a load value of 50 gduring the Compression Portion of the Wet Compression Test Method asmeasured according to the Wet Compression Test Method described herein.

In yet another example of the present invention, a fibrous structure ofthe present invention exhibits at least one Wet Compression value in aload value range of from 50 g to 300 g during the Relaxation Portion ofthe Wet Compression Test Method that is statistically greater than thecorresponding Wet Compression value of the same fibrous structure voidof the wet compression-enhancing agent as measured according to the WetCompression Test Method. In another example, a fibrous structure of thepresent invention exhibits at least one Wet Compression value in a loadvalue range of from 50 g to 300 g during the Relaxation Portion of theWet Compression Test Method that is greater than the corresponding WetCompression value of the same fibrous structure void of the wetcompression-enhancing agent as measured according to the Wet CompressionTest Method. In even another example of the present invention, a fibrousstructure exhibits at least one Wet Compression value in the load valuerange of from 50 g to 300 g during the Relaxation Portion of the WetCompression Test Method that is greater than the corresponding WetCompression value of the same fibrous structure void of the wetcompression-enhancing agent by at least 0.010 mm as measured accordingto the Wet Compression Test Method described herein.

In still another example of the present invention, a fibrous structureof the present invention exhibits at least one Wet Compression value inthe load value range of from 50 g to 300 g during the Relaxation Portionof the Wet Compression Test Method that is greater than thecorresponding Wet Compression value of the same fibrous structure voidof the wet compression-enhancing agent by at least 0.012 mm as measuredaccording to the Wet Compression Test Method. In another example, afibrous structure exhibits at least one Wet Compression value in theload value range of from 50 g to 300 g during the Relaxation Portion ofthe Wet Compression Test Method that is greater than the correspondingWet Compression value of the same fibrous structure void of the wetcompression-enhancing agent by at least 0.014 mm as measured accordingto the Wet Compression Test Method described herein.

In one example, a fibrous structure of the present invention exhibits aWet Compression value of greater than 0.444 mm at a load value of 300 gduring the Relaxation Portion of the Wet Compression Test Method and/ora Wet Compression value of greater than 0.452 mm at a load value of 200g during the Relaxation Portion of the Wet Compression Test Methodand/or a Wet Compression value of greater than 0.463 mm at a load valueof 150 g during the Relaxation Portion of the Wet Compression TestMethod and/or a Wet Compression value of greater than 0.471 mm at a loadvalue of 125 g during the Relaxation Portion of the Wet Compression TestMethod and/or a Wet Compression value of greater than 0.484 mm at a loadvalue of 100 g during the Relaxation Portion of the Wet Compression TestMethod and/or a Wet Compression value of greater than 0.503 mm at a loadvalue of 75 g during the Relaxation Portion of the Wet Compression TestMethod and/or a Wet Compression value of greater than 0.536 mm at a loadvalue of 50 g during the Relaxation Portion of the Wet Compression TestMethod as measured according to the Wet Compression Test Methoddescribed herein.

In one example, the fibrous structure of the present invention comprisesa multi-ply fibrous structure, for example a two-ply fibrous structure,wherein the wet compression-enhancing agent is contained on/in one orboth plies.

Wet Compression-Enhancing Agents

The wet compression-enhancing agents of the present invention may be anysuitable material, such as a polymer, for example a water-solublepolymer, that when applied to and/or present within a fibrous structureprovides the fibrous structure at least one of the following properties:

a. at least one Wet Compression value in a load value range of from 100g to 300 g during the Compression Portion of the Wet Compression TestMethod that is statistically greater than the corresponding WetCompression value of the same fibrous structure void of the wetcompression-enhancing agent as measured according to the Wet CompressionTest Method described herein; and

b. at least one Wet Compression value in a load value range of from 50 gto 300 g during the Relaxation Portion of the Wet Compression TestMethod that is statistically greater than the corresponding WetCompression value of the same fibrous structure void of the wetcompression-enhancing agent as measured according to the Wet CompressionTest Method described herein. In one example the fibrous structureexhibits both (a) and (b) properties described above.

The wet compression-enhancing agents do not include permanent and/ortemporary wet strength agents that form amidol and/or hemiacetal bondswith each other and/or with pulp fibers within a fibrous structure, suchas polyamide-epichlorohydrin crosslinking agents, for example Kymene®and polyacrylamide-based crosslinking agents, for example Hercobond®both commercially available from Ashland Inc. In other words, the scopeof the present invention explicitly excludes materials that increase thewet tensile strength of a fibrous structure by crosslinking with eachother and/or with pulp fibers within a fibrous structure.

The wet compression-enhancing agents of the present invention may behomopolymers, such as homopolymer of the acrylamide monomer (i.e.,polyacrylamide), and/or a copolymer or terpolymer or other polymerderived from four or more monomers. In one example, the wetcompression-enhancing agent comprises a homopolymer of acrylamidemonomers; namely, polyacrylamide.

In one example, the charge and charge density of the wetcompression-enhancing agent may be altered/adjusted by including chargedmonomers, such as anionically charged monomers and/or cationicallycharged monomers. For example, an anionic polyacrylamide may be preparedby copolymerization of acrylamide monomers and anionic acrylic acidmonomers with charge density impacted by the ratio of monomers utilized.Anionic formulas utilize AE (anionic emulsion) or AD (anionic dewateredemulsion) nomenclature. Whereas cationic polyacrylamide may be preparedby copolymerization of acrylamide monomers and a cationic ester monomersuch as chloromethylated acrylic monomer with charge density impacted bythe ratio of monomers utilized. Cationic formulas utilize CE (cationicemulsion) or CD (cationic dewatered emulsion) nomenclature. In addition,amphoteric polyacrylamide may be prepared by copolymeration ofacrylamide monomers, anionic acrylic acid monomers and a cationic estermonomer.

In one example, the wet compression-enhancing agent comprises an anionicpolyacrylamide having a weight average molecular weight of from about7,000,000 g/mol to about 30,000,000 g/mol.

In another example, the wet compression-enhancing agent comprises acationic polyacrylamide having a weight average molecular weight of fromabout 2,000,000 g/mol to about 12,000,000 g/mol.

In one example, the wet compression-enhancing agent exhibits a weightaverage molecular weight of greater than 750,000 and/or greater than1,500,000 and/or greater than 4,000,000 and/or to about 40,000,000and/or to about 20,000,000 and/or to about 10,000,000 g/mol.

In another example, the wet compression-enhancing agent exhibits anumber average molecular weight of greater than 200,000 g/mol and/orgreater than 500,000 g/mol and/or greater than 750,000 g/mol and/orgreater than 900,000 g/mol to less than 2,000,000 g/mol and/or less than1,750,000 g/mol and/or less than 1,500,000 g/mol. In one example, thewet compression-enhancing agent exhibits a number average molecularweight of from about 500,000 g/mol to about 2,000,000 g/mol and/or fromabout 900,000 g/mol to about 1,700,000 g/mol.

In one example, the wet compression-enhancing agent of the presentinvention exhibits an average particle size distribution of less than5000 d·nm and/or less than 3000 d·nm and/or less than 2000 d·nm and/orgreater than 10 d·nm and/or greater than 100 d·nm and/or greater than500 d·nm and/or greater than 1000 d·nm.

In one example, the wet compression-enhancing agent comprises a polymercomprising monomeric units derived from acrylic acid and/or quaternaryammonium compounds and/or acrylamide. In one example,polyethyleneimines, such as Lupasol®, which is commercially availablefrom BASF Corporation, are not suitable as wet compression-enhancingagents within the present invention.

In one example, the wet compression-enhancing agent comprises aflocculating agent as compared to a coagulating agent.

A flocculating agent is a chemical that results in colloids and othersuspended particles, especially in liquids, to aggregate. An example ofa flocculating agent according to the present invention is Rhodia'sMirapol®.

A coagulating agent on the other hand, for purposes of the presentinvention is a chemical that results in a liquid changing into athickened solid. An example of a coagulating agent according to thepresent invention is BASF Corporation's Lupasol®.

In one example, the wet compression-enhancing agent comprises ahomopolymer of polyacrylamide, such as Hyperfloc®, which is commerciallyavailable from Hychem, Inc. The wet compression-enhancing agent maycomprise an anionic polyacrylamide, a nonionic polyacrylamide and/or acationic polyacrylamide. In one example, the wet compression-enhancingagent comprises a cationic polyacrylamide.

In one example, the wet compression-enhancing agent may be used as ahighly concentrated inverse emulsion (for example a water-in-oilemulsion), containing greater than 10% and/or greater than 15% and/orgreater than 20% and/or greater than 25% and/or greater than 30% and/orgreater than 35% and/or to about 60% and/or to about 55% and/or to about50% and/or to about 45% active. The oil phase may consist of highquality mineral oil with boiling point range of 468-529° F. or a heavymineral oil with boiling point range of 608-968° F. In another examplethe wet compression-enhancing agents may be used as a highlyconcentrated dewatered emulsion for example dry particles suspended in acontinuous oil phase, containing greater than 10% and/or greater than15% and/or greater than 20% and/or greater than 25% and/or greater than30% and/or greater than 35% and/or to about 60% and/or to about 55%and/or to about 50% and/or to about 45% active. The oil phase mayconsist of high quality mineral oil with boiling point range of 468-529°F. or a heavy mineral oil with boiling point range of 608-968° F. In oneexample, the oil phase of the dewatered emulsion comprises a hydrocarbonfluid, such as white mineral oil, that exhibits a VOC content of lessthan 60% as measured according to the VOC Test Method and an emulsifyingsurfactant and/or inverting surfactant. In addition, the soil adsorbingagent of the dewatered emulsion may exhibit a net charge density ofgreater than −5 meq/g to less than 5 meq/g and/or from greater than −5to about −0.1 meq/g as measured according to the Charge Density TestMethod, described herein. In still another example, the soil adsorbingagent may exhibit a UL Viscosity of from about 1 to about 6 cP asmeasured according to the UL Viscosity Test Method described herein.

In one example, the wet compression-enhancing agent may be used as ahighly concentrated inverse emulsion wherein the continuous phase of theinverse emulsion comprises mineral oil, such as white mineral oil.

In still another example, the wet compression-enhancing agent may beused as a dewatered inverse emulsion, such as Hyperfloc® ND823, AD589,and CD864, which are commercially available from SNF Floerger and/orHychem, Inc., which consist of micron size particles of highly coiledpolymer in a continuous oil phase.

The inverse emulsions of the present invention may be directly appliedto a surface of a fibrous structure, such as a surface of a dry fibrousstructure, a surface of a wet fibrous structure and/or added to thewet-end of a papermaking process.

In one example, the wet compression-enhancing agent comprises a blend oftwo or more wet compression-enhancing agents. In one example, the wetcompression-enhancing agent comprises a blend of a polyacrylamidewater-in-oil emulsion (such as Hyperfloc® NE823F) and a polyacrylamidedewatered inverse emulsion (such as Hyperfloc® ND823). In one example,the blend comprises 50% by volume or greater and/or 60% or greater byvolume and/or 75% or greater by volume and/or 80% by volume or greater.

In one example of the present invention, the soil adsorbing agentpresent in the article of manufacture exhibits a volatile organiccontent (VOC) of less than 20% and/or less than 15% and/or less than 10%and/or less than 5% as measured according to the VOC Test Methoddescribed herein. In another example, an article of manufacture of thepresent invention comprises a first soil adsorbing agent that exhibits aVolatile Organic Carbon content (VOC) of greater than 20% and a secondsoil adsorbing agent that exhibits a Volatile Organic Carbon content(VOC) of less than 20% and/or less than 15% and/or less than 10% and/orless than 5% as measured according to the VOC Test Method describedherein.

In another example of the present invention, the soil adsorbing agentpresent in the article of manufacture exhibits a Total Volatiles contentof less than 55% and/or less than and/or less than 50% and/or less than45% and/or less 40% and/or less than 40% and/or less than 35% and/orless than 25% and/or less than 15% as measured according to the VOC TestMethod described herein.

In another example of the present invention, the soil adsorbing agentpresent in the article of manufacture exhibits a Moisture content ofless than 30% and/or less than 25% and/or less than 20% and/or less than15% as measured according to the VOC Test Method described herein.

Table 1 below illustrates Total Volatiles content, Moisture content, andVolatile Organic Carbon content (as measured according to the VOC TestMethod described herein) of examples of wet compression-enhancingagents, in this case nonionic polyacrylamides; namely, Hyperfloc®NE823E, Hyperfloc® NE823F, and Hyperfloc® ND823 (commercially availablefrom SNF Floerger and/or Hychem, Inc.) alone and in blends with eachother prepared from commercially available materials.

TABLE 1 Total Volatiles Moisture VOC Hyperfloc Material (%) (%) (%)NE823E 60.1 37.4 22.7 NE823F lot RA07/1310 57.3 35.7 21.6 NE823F lotRA10/1276 57.6 35.0 22.6 NE823F lot RA10/1216 57.1 36.9 20.2 NE823F lotRA07/1307 57.2 36.4 20.9 NE823F lot RA06/1309 56.9 35.4 21.5 AverageNE823F 57.2 35.9 21.4 Std. Dev. 0.24 0.75 0.87 ND823 lot DA06/1216 14.045.31 8.73 Calculated 25/75 Blend of 24.83 12.93 11.90 NE823F/ND823 50/50Blend of 35.62 28.25 15.01 NE823F/ND823 75/25 Blend of 46.41 28.25 18.22NE823F/ND823 Measured 25/75 Blend of 14.2 10.5 3.7 NE823F/ND823 50/50Blend of 29.9 17.6 12.3 NE823F/ND823 75/25 Blend of 44.0 23.3 20.7NE823F/ND823

Table 2 below illustrates the impact of incorporating a wetcompression-enhancing agent, in this case an anionic polyacrylamide wetcompression-enhancing agent, into a fibrous structure, a paper towel,such as a wet-laid, through-air dried (TAD), wet microcontracted, 2-plypaper towel. The Wet Compression Values for loads C5 to C75 and R5 toR25 are statistically different.

TABLE 2 Control Fibrous Invention A Structure 2-ply Fibrous (No wetStructure compression- NE823F enhancing agent) (1.3 #/ton) Load (g) (mm)(mm) C5 1.208 1.308 C10 1.139 1.198 C25 1.025 1.058 C50 0.905 0.926 C750.810 0.828 C100 0.733 0.746 C125 0.670 0.681 C150 0.619 0.628 C2000.543 0.549 C300 0.451 0.453 R5 0.697 0.773 R10 0.657 0.710 R25 0.5860.611 R50 0.531 0.541 R75 0.503 0.509 R100 0.486 0.490 R125 0.475 0.478R150 0.467 0.470 R200 0.457 0.459 R300 0.449 0.451

Table 3 below illustrates the impact of incorporating a 50/50 mixture(blend) of two wet compression-enhancing agent, in this case an anionicpolyacrylamide wet compression-enhancing agent and a nonionicpolyacrylamide wet compression-enhancing agent, into a fibrousstructure, a paper towel, such as a wet-laid, through-air dried (TAD),wet microcontracted, 2-ply paper towel. The Wet Compression Values forloads C25 to C75 and C300 and R5 to R300 are statistically different.

TABLE 3 Control Fibrous Invention B Structure 2-ply Fibrous (No wetStructure compression- 50/50 NE823F/ND823 enhancing agent) (1.3 #/ton)Load (g) (mm) (mm) C5 1.258 1.287 C10 1.154 1.179 C25 1.014 1.037 C500.884 0.906 C75 0.789 0.808 C100 0.713 0.729 C125 0.651 0.666 C150 0.6010.614 C200 0.526 0.539 C300 0.435 0.446 R5 0.751 0.766 R10 0.685 0.701R25 0.587 0.601 R50 0.521 0.533 R75 0.489 0.502 R100 0.471 0.483 R1250.460 0.471 R150 0.451 0.463 R200 0.441 0.452 R300 0.433 0.444

Table 4 below illustrates the impact of incorporating a wetcompression-enhancing agent, in this case a nonionic polyacrylamide wetcompression-enhancing agent, into a fibrous structure, a paper towel,such as a wet-laid, through-air dried (TAD), wet microcontracted, 2-plypaper towel. The Wet Compression Values for loads C50 to C300 and R50 toR300 are statistically different.

TABLE 4 Control Fibrous Structure Invention C (No wet 2-ply FibrousStructure compression- ND823 enhancing agent) (1.3 #/ton) Load (g) (mm)(mm) C5 1.305 1.292 C10 1.193 1.199 C25 1.052 1.067 C50 0.922 0.937 C750.823 0.838 C100 0.741 0.758 C125 0.675 0.691 C150 0.621 0.637 C2000.542 0.557 C300 0.445 0.458 R5 0.776 0.776 R10 0.710 0.714 R25 0.6070.617 R50 0.535 0.548 R75 0.502 0.515 R100 0.483 0.496 R125 0.470 0.483R150 0.462 0.475 R200 0.451 0.464 R300 0.443 0.456

In one example, the wet compression-enhancing agent of the presentinvention is water-soluble.

In another example, the wet compression-enhancing agent of the presentinvention comprises a linear polymer. In still another example, the wetcompression-enhancing agent comprises a branched polymer. In yet anotherexample, the wet compression-enhancing agent comprises a crosslinkedpolymer.

Processes for Making Fibrous Structure

The fibrous structure of the present invention may be made by anysuitable process known in the art. For example, if the fibrous structureis a web, any suitable web making process can be used.

In one example, the fibrous structure may be made by a processcomprising the step of contacting a surface of the fibrous structurewith a wet compression-enhancing agent according to the presentinvention. We have surprisingly found that direct application of thehigh active content water in oil emulsion to the dry sheet can beaccomplished without significantly disrupting the sheet structure andproviding for improved VFS absorbent capacity in much the same way assuperabsorbent polymers without the negative consumer responseassociated with release of visible super absorbent gel particlescontaminating the surface being cleaned or the consumers hands.

In another example of a process for making a fibrous structure,comprises the steps of:

-   -   a. providing a fiber slurry;    -   b. depositing the fiber slurry onto a foraminous wire to form an        embryonic web;    -   c. drying the embryonic web to produce a fibrous structure; and    -   d. contacting the fibrous structure with a wet        compression-enhancing agent to produce a fibrous structure (for        example a dry fibrous structure) in accordance with the present        invention.

In yet another example of a process for making a fibrous structure,comprises the steps of:

-   -   a. providing a fiber slurry comprising a wet        compression-enhancing agent;    -   b. depositing the fiber slurry onto a foraminous wire to form an        embryonic web; and    -   c. drying the embryonic web to produce a fibrous structure (for        example a dry fibrous structure) in accordance with the present        invention; and    -   d. optionally, contacting the fibrous structure with a wet        compression-enhancing agent.

The fiber slurry may comprise permanent and/or temporary wet strengthagents such as Kymene® (permanent wet strength) and Hercobond®(temporary wet strength) both available from Ashland Inc.

In still yet another example of a process for making an air-laid fibrousstructure comprises the steps of:

-   -   a. providing pulp fibers;    -   b. producing an air-laid fibrous structure from the pulp fibers;        and    -   c. contacting a surface of the air-laid fibrous structure with a        wet compression-enhancing agent according to the present        invention.

In one example, the wet compression-enhancing agent may be added to afibrous structure of the present invention during papermaking, betweenthe Yankee dryer and the reel, and/or during converting by applying itto one or more surfaces of the fibrous structure. In one example, asingle-ply paper towel comprises the wet compression-enhancing agent onone surface of the paper towel. In another example, a single-ply papertowel comprises the wet compression-enhancing agent on both surfaces ofthe paper towel. In still another example, a two-ply paper towelcomprises the wet compression-enhancing agent on one or both exteriorsurfaces of the two-ply paper towel. In still another example, a two-plypaper towel comprises the wet compression-enhancing agent on one or moreinterior surfaces of the two-ply paper towel. In yet another example, atwo-ply paper towel comprises the wet compression-enhancing agent on oneor more exterior surfaces and one or more interior surfaces of thetwo-ply paper towel. One of ordinary skill would understand thatexterior surfaces and various interior surfaces of a three or more plypaper towel could comprise the wet compression-enhancing agent.

In one example, the fibrous structure may be made by adding a wetcompression-enhancing agent into the wet end of a wet laid papermakingprocess. In other words, the wet compression-enhancing agent may beadded to a fiber slurry comprising hardwood and/or softwood fibers priorto depositing the slurry onto a foraminous wire.

In another example, the fibrous structure of the present invention maybe made by printing a wet compression-enhancing agent onto a surface ofa fibrous structure, for example in a converting operation. The printingoperation may occur by any suitable printing equipment, for example byway of a gravure roll.

In still another example, an fibrous structure of the present inventionmay be made by extruding a wet compression-enhancing agent onto asurface of a fibrous structure during one or more converting operations.

In even another example, a fibrous structure of the present inventionmay be made by spraying a wet compression-enhancing agent onto a surfaceof a fibrous structure.

In yet another example, a fibrous structure of the present invention maybe made by spraying a wet compression-enhancing agent onto a wet fibrousstructure during papermaking after the vacuum dewatering step, butbefore the predryers and/or after the predryers, but before the Yankee.

In one example, one or more wet compression-enhancing agents may beadded to a fibrous structure in the wet-end, in the fibers prior toinclusion into a fiber slurry, and/or during papermaking and/or duringconverting of the fibrous structure and/or to a finished fibrousstructure, such as a paper towel. For example, a first wetcompression-enhancing agent may be added to a fibrous structure in thewet-end and second wet compression-enhancing agent, the same ordifferent as the first, may be added to the fibrous structure duringpapermaking and/or converting.

A wet compression-enhancing agent comprising Hyperfloc® NE823Frepresents an APE free, non-ionic water-in-oil emulsion (about 30%active-about 30% polyacrylamide, 30% water, 30% high boiling oil, and10% surfactants) available from Hychem, Inc. under the trade nameNE823F. A wet compression-enhancing agent comprising Hyperfloc® ND823represents a dewatered emulsion consisting of (about 50% active-about50% polyacrylamide, 40% high boiling oil and 10% surfactants). A blend(mixture) of the Hyperfloc® NE823F and ND823, for example via low shearmixing, result in a stable emulsion with no obvious settling.Formulations ranging from 100% NE823F to 100% ND823 were found to bestable with minimal short duration low shear mixing as is typicallyrecommend with water in oil emulsion products. A 50/50 volume blend isprepared. Other blends such as 25/75 and/or 75/25 by volume of NE823Fand ND823 may be utilized. The Hyperfloc® 50/50 volume blend emulsion ofNE823F/ND823 is applied directly to an embossed surface of a fibrousstructure via an extruder in converting utilizing an S-wrapconfiguration such that the extruder is positioned below the sheet withfull wrap over the extruder head. Alternatively, dual side extrusion maybe utilized.

In even yet another example, a fibrous structure of the presentinvention may be made by depositing a plurality of fibers mixed with awet compression-enhancing agent in an air-laid and/or coform process.

In still another example, a fibrous structure may be made that containswet compression-enhancing agents by including the wetcompression-enhancing agents at acceptable locations within spunbonding,meltblowing, carding, and/or hydroentangling processes.

The wet compression-enhancing agent may be applied to and/or included ina fibrous structure in a pattern, such as a non-random, repeatingpattern. In one example, the wet compression-enhancing agent may bephase registered with embossments in the fibrous structure, wet moldedtexture in the fibrous structure, perforations in the fibrous structure,and/or printing on the fibrous structure.

Non-Limiting Examples Example 1

Articles of manufacture, in particular fibrous structures; namely, papertowels are produced utilizing a cellulose furnish consisting of aNorthern Softwood Kraft (NSK) and Eucalyptus Hardwood (EUC) at a ratioof approximately 65/35. The NSK is refined as needed to maintain targetwet burst at the reel. Any furnish preparation and refining methodologycommon to the papermaking industry can be utilized.

A 3% active solution Kymene 1142 is added to the refined NSK line priorto an in-line static mixer and 1% active solution of Wickit 1285, anethoxylated fatty alcohol defoamer available from Ashland Inc. is addedto the EUC furnish. The addition levels are 20 and 1 lbs active/ton ofpaper, respectively.

The NSK and EUC thick stocks are then blended into a single thick stockline followed by addition of 1% active carboxymethylcellulose (CMC)solution at 7 lbs active/ton of paper towel, and optionally, a softeningagent may be added.

The thick stock is then diluted with white water at the inlet of a fanpump to a consistency of about 0.15% based on total weight of NSK andEUC fiber. The diluted fiber slurry is directed to a non-layeredconfiguration headbox such that a wet web produced from the fiber slurryis formed onto a Fourdrinier wire (foraminous wire).

Dewatering occurs through the Fourdrinier wire and is assisted bydeflector and vacuum boxes. The Fourdrinier wire is of a 5-shed, satinweave configuration having 84 machine-direction and 78 cross-directionmonofilaments per inch, respectively. The speed of the Fourdrinier wireis about 675 fpm (feet per minute).

The embryonic wet web is transferred from the Fourdrinier wire at afiber consistency of about 22% at the point of transfer to a patternedbelt through-air-drying resin carrying fabric. To provide fibrousstructure products of the present invention, the speed of the patternedthrough-air-drying fabric is about 18% slower than the speed of theFourdrinier wire (for example a wet molding process). In anotherexample, the embryonic wet web may be transferred to a patterned beltand/or fabric where the speed of the patterned through-air-drying fabricis approximately the same as the speed of the Fourdrinier wire.

Further de-watering is accomplished by vacuum assisted drainage untilthe web has a fiber consistency of about 26-28%.

While remaining in contact with the patterned drying fabric, the web ispre-dried by air blow-through pre-dryers to a fiber consistency of about65% by weight.

After the pre-dryers, the semi-dry web is transferred to a Yankee dryerand adhered to the surface of the Yankee dryer with a sprayed crepingadhesive. The creping adhesive is an aqueous dispersion with the activesconsisting of about 2#/ton polyvinyl alcohol, and 0.5#/ton of releaseaid (CREPETROL® R6390). Crepe aids such as CREPETROL® A3025 may also beutilized. CREPETROL® A3025 and CREPETROL® R6390 are commerciallyavailable from Ashland Inc. (formerly Hercules Inc.). The crepingadhesive is delivered to the Yankee surface at a rate of about 0.15%adhesive solids based on the dry weight of the web. The fiberconsistency is increased to about 97% before the web is dry creped fromthe Yankee with a doctor blade.

The doctor blade has a bevel angle of about 45° and is positioned withrespect to the Yankee dryer to provide an impact angle of about 101°.The Yankee dryer is operated at a temperature of about 177° C. and aspeed of about 550 fpm. The fibrous structure is wound in a roll using asurface driven reel drum having a surface speed of about 610 fpm. Inanother example, the doctor blade may have a bevel angle of about 25°and is positioned with respect to the Yankee dryer to provide an impactangle of about 81° and the reel is run about 10% slower than the speedof the Yankee.

A first wet compression-enhancing agent comprising a dewatered(dehydrated) Hyperfloc® emulsion of micron size polymer particlesdispersed in oil (about 50% active-about 50% polyacrylamide, 40% highboiling oil, and 10% surfactants) available from Hychem, Inc. under thetrade name ND823 is applied directly to a surface of a fibrous structurein the converting operation via an extruder to the embossed side of atwo ply product. Additionally, a second extruder can be utilized toapply soil attracting polymer to the un-embossed side of the sheet.

A second wet compression-enhancing agent comprising a Hyperfloc®water-in-oil emulsion (about 30% active-about 30% polyacrylamide, 30%water, 30% high boiling oil, and 10% surfactants) with the activepolymer consisting of highly coiled polymer dissolved in micron sizewater droplets available from Hychem, Inc. under the trade name NE823F,which is the non-dewatered (non-dehyrdated) form of Hyperfloc® ND823, isapplied directly to a surface of a fibrous structure via a sprayapplication in papermaking onto the fabric side and/or the wire side ofthe dry fibrous structure between the calender and the reel.Alternatively extruder application in converting can be utilized.

The fibrous structure may be embossed prior to and/or subsequent to theapplication of one or both of the wet compression-enhancing agents. Itmay then be subsequently converted into a two-ply paper towel producthaving a basis weight of about 28-33 lbs/3000 ft² with fabric side outand/or wire side out.

Example 2

Articles of manufacture, in particular fibrous structures; namely, papertowels are produced utilizing a cellulose furnish consisting of aNorthern Softwood Kraft (NSK) and Eucalyptus Hardwood (EUC) at a ratioof approximately 70/30. The NSK is refined as needed to maintain targetwet burst at the reel. Any furnish preparation and refining methodologycommon to the papermaking industry can be utilized.

A 3% active solution Kymene 1142 is added to the refined NSK line priorto an in-line static mixer and 1% active solution of Wickit 1285, anethoxylated fatty alcohol defoamer available from Ashland Inc. is addedto the EUC furnish. The addition levels are 20 and 1 lbs active/ton ofpaper, respectively.

The NSK and EUC thick stocks are then blended into a single thick stockline followed by addition of 1% active carboxymethylcellulose (CMC)solution at 7 lbs active/ton of paper towel, and optionally, a softeningagent may be added.

The thick stock is then diluted with white water at the inlet of a fanpump to a consistency of about 0.15% based on total weight of NSK andEUC fiber. The diluted fiber slurry is directed to a non-layeredconfiguration headbox such that a wet web produced from the fiber slurryis formed onto a Fourdrinier wire (foraminous wire).

Dewatering occurs through the Fourdrinier wire and is assisted bydeflector and vacuum boxes. The Fourdrinier wire is of a 5-shed, satinweave configuration having 84 machine-direction and 78 cross-directionmonofilaments per inch, respectively. The speed of the Fourdrinier wireis about 675 fpm (feet per minute).

The embryonic wet web is transferred from the Fourdrinier wire at afiber consistency of about 22% at the point of transfer to a patternedbelt through-air-drying resin carrying fabric. To provide fibrousstructure products of the present invention, the speed of the patternedthrough-air-drying fabric is about 18% slower than the speed of theFourdrinier wire (for example a wet molding process). In anotherexample, the embryonic wet web may be transferred to a patterned beltand/or fabric where the speed of the patterned through-air-drying fabricis approximately the same as the speed of the Fourdrinier wire.

Further de-watering is accomplished by vacuum assisted drainage untilthe web has a fiber consistency of about 26-28%.

While remaining in contact with the patterned drying fabric, the web ispre-dried by air blow-through pre-dryers to a fiber consistency of about65% by weight.

After the pre-dryers, the semi-dry web is transferred to a Yankee dryerand adhered to the surface of the Yankee dryer with a sprayed crepingadhesive. The creping adhesive is an aqueous dispersion with the activesconsisting of about 2#/ton polyvinyl alcohol, and 0.5#/ton of releaseaid (CREPETROL® R6390). Crepe aids such as CREPETROL® A3025 may also beutilized. CREPETROL® A3025 and CREPETROL® R6390 are commerciallyavailable from Ashland Inc. (formerly Hercules Inc.). The crepingadhesive is delivered to the Yankee surface at a rate of about 0.15%adhesive solids based on the dry weight of the web. The fiberconsistency is increased to about 97% before the web is dry creped fromthe Yankee with a doctor blade.

The doctor blade has a bevel angle of about 45° and is positioned withrespect to the Yankee dryer to provide an impact angle of about 101°.The Yankee dryer is operated at a temperature of about 177° C. and aspeed of about 550 fpm. The fibrous structure is wound in a roll using asurface driven reel drum having a surface speed of about 610 fpm. Inanother example, the doctor blade may have a bevel angle of about 25°and is positioned with respect to the Yankee dryer to provide an impactangle of about 81° and the reel is run about 10% slower than the speedof the Yankee.

A wet compression-enhancing agent comprising Hyperfloc® NE823Frepresents an APE free, non-ionic water-in-oil emulsion (about 30%active-about 30% polyacrylamide, 30% water, 30% high boiling oil, and10% surfactants) available from Hychem, Inc. under the trade nameNE823F. A wet compression-enhancing agent comprising Hyperfloc® ND823represents a dewatered emulsion consisting of (about 50% active-about50% polyacrylamide, 40% high boiling oil and 10% surfactants). A blend(mixture) of the Hyperfloc® NE823F and ND823, for example via low shearmixing, result in a stable emulsion with no obvious settling.Formulations ranging from 100% NE823F to 100% ND823 were found to bestable. A 50/50 volume blend is prepared. The Hyperfloc® 50/50 volumeblend emulsion of NE823F/ND823 is applied directly to an embossedsurface of a fibrous structure via an extruder in converting utilizingan S-wrap configuration such that the extruder is positioned below thesheet with full wrap over the extruder head. Alternatively, dual sideextrusion may be utilized.

The fibrous structure may be subsequently converted into an embossed,two-ply paper towel product having a basis weight of about 28-33lbs/3000 ft² with fabric side out and/or wire side out.

Test Methods

Unless otherwise specified, all tests described herein including thosedescribed under the Definitions section and the following test methodsare conducted on samples that have been conditioned in a conditionedroom at a temperature of 23° C.±1.0° C. and a relative humidity of50%±2% for a minimum of 2 hours prior to the test. All plastic and paperboard packaging articles of manufacture must be carefully removed fromthe paper samples prior to testing. The samples tested are “usableunits.” “Usable units” as used herein means sheets, flats from rollstock, pre-converted flats, and/or single or multi-ply products. Exceptwhere noted all tests are conducted in such conditioned room, all testsare conducted under the same environmental conditions and in suchconditioned room. Discard any damaged product. Do not test samples thathave defects such as wrinkles, tears, holes, and like. Samplesconditioned as described herein are considered dry samples (such as “dryfilaments”) for testing purposes. All instruments are calibratedaccording to manufacturer's specifications.

Basis Weight Test Method

Basis weight of a fibrous structure is measured on stacks of twelveusable units using a top loading analytical balance with a resolution of±0.001 g. The balance is protected from air drafts and otherdisturbances using a draft shield. A precision cutting die, measuring3.500 in ±0.0035 in by 3.500 in ±0.0035 in is used to prepare allsamples.

With a precision cutting die, cut the samples into squares. Combine thecut squares to form a stack twelve samples thick. Measure the mass ofthe sample stack and record the result to the nearest 0.001 g.

The Basis Weight is calculated in lbs/3000 ft² or g/m² as follows:

Basis Weight=(Mass of stack)/[(Area of 1 square in stack)×(No. ofsquares in stack)]

For example,

Basis Weight (lbs/3000 ft²)=[[Mass of stack (g)/453.6 (g/lbs)]/[12.25(in²)/144 (in²/ft²)×12]]×3000

or,

Basis Weight (g/m²)=Mass of stack (g)/[79.032 (cm²)/10,000 (cm²/m²)×12]

Report result to the nearest 0.1 lbs/3000 ft² or 0.1 g/m². Sampledimensions can be changed or varied using a similar precision cutter asmentioned above, so as at least 100 square inches of sample area instack.

Moisture Content Test Method

The moisture content present in a fibrous structure, such as a fibrousstructure is measured using the following Moisture Content Test Method.A fibrous structure or portion thereof (“sample”) is placed in aconditioned room at a temperature of 23° C.±1.0° C. and a relativehumidity of 50%±2% for at least 24 hours prior to testing. Each fibrousstructure sample has an area of at least 4 square inches, but smallenough in size to fit appropriately on the balance weighing plate. Underthe temperature and humidity conditions mentioned above, using a balancewith at least four decimal places, the weight of the sample is recordedevery five minutes until a change of less than 0.5% of previous weightis detected during a 10 minute period. The final weight is recorded asthe “equilibrium weight”. Within 10 minutes, the sample is placed into aforced air oven on top of foil for 24 hours at 70° C.±2° C. at arelative humidity of 4%±□2% for drying. After the 24 hours of drying,the sample is removed and weighed within 15 seconds. This weight isdesignated as the “dry weight” of the sample.

The moisture content of the sample is calculated as follows:

${\% \mspace{14mu} {Moisture}\mspace{14mu} {in}\mspace{14mu} {sample}} = {100\% \times \frac{\begin{pmatrix}{{{Equilibrium}\mspace{14mu} {weight}\mspace{14mu} {of}\mspace{14mu} {sample}} -} \\{{Dry}\mspace{14mu} {weight}\mspace{14mu} {of}\mspace{14mu} {sample}}\end{pmatrix}}{{Dry}\mspace{14mu} {weight}\mspace{14mu} {of}\mspace{14mu} {sample}}}$

The % Moisture in sample for 3 replicates is averaged to give thereported % Moisture in sample. Report results to the nearest 0.1%.

Wet Compression Test Method

The Wet Compression Value of a fibrous structure and/or sanitary tissueproduct is measured by as follows. Caliper versus load data are obtainedusing a Thwing-Albert Model EJA Materials Tester, equipped with a 2000 gload cell and compression fixture including a compression table(compression platen). The compression fixture consists of the following:a load cell adaptor plate, 2000 gram overload protected load cell, loadcell adaptor/foot mount 1.128 inch diameter presser foot, #89-14 anvil,89-157 leveling plate, anvil mount, and a grip pin, all available fromThwing-Albert Instrument Company, Philadelphia, Pa. The compression foothas an area is 1 in². The instrument is run under the control ofThwing-Albert Motion Analysis Presentation Software (MAP V1,1,6,9). Atest sample in the shape of a circle having a diameter of approximately2 inches is cut from a usable unit to be tested (the test sample must beless than 2.5 inches in diameter (the diameter of the anvil) to preventinterference of the compression fixture with the test sample beingtested). Care should be taken to avoid damage to the center portion ofthe test sample, which will be under test. Scissors or other suitablecutting tools may be used. Just before the test execution, the testsample is saturated with 4.5 g water/g fiber to produce a wet testsample. For the test, the wet test sample is centered on the compressiontable under the compression foot. The Tester is turned on. Thecompression-relaxation procedure is repeated 3 times on the same wettest sample. The compression and relaxation portion data are obtainedusing a crosshead speed of 0.1 inches/minute. The deflection of the loadcell is obtained by running the test without a test sample being presenton the compression table. This is generally known as the Steel-to-Steeldata. The Steel-to-Steel data are obtained at a crosshead speed of 0.005inch/minute. Crosshead position and load cell data are recorded betweenthe load cell range of 5 grams and 300 grams for both the compressionand relaxation portions of the test. Since the compression foot area is1 in² this corresponded to a range of 5 g/in² to 300 g/in². The maximumpressure exerted on the wet test sample is 300 g/in². At 300 g/in² thecrosshead reverses its travel direction. Crosshead position values arecollected at selected load values during the test. These correspond topressure values of 5, 10, 25, 50, 75, 100, 125, 150, 200, 300, 200, 150,125, 100, 75, 50, 25, 10, 5 g/in² for the compression and the relaxationdirection. During the compression portion of the test, crossheadposition values are collected by the MAP software, by defining 10 traps(Trap 1 to Trap 10) at load settings of 5 (C5), 10 (C10), 25 (C25), 50(C50), 75 (C75), 100 (C100), 125 (C125), 150 (C150), 200 (C200), 300(C300) g/in². During the relaxation (return) portion of the test,crosshead position values are collected by the MAP software, by definingten return traps (Return Trap 1 to Return Trap 10) at load settings of300 (R300), 200 (R200), 150 (R150), 125 (R125), 100 (R100), 75 (R75), 50(R50), 25 (R25), 10 (R10), 5 (R5) g/in². This cycle of compressions to300 g/in² and return to 5 g/in² is repeated 3 times on the same wet testsample without removing the wet test sample. The 3 cyclecompression-relaxation test is replicated 5 times for a given fibrousstructure and/or sanitary tissue product using a fresh usable unit eachtime. The result (wet caliper of the wet test sample) is reported as anaverage of the 5 replicates for a given load. Again the caliper valuesare obtained for both the Steel-to-Steel and the wet test sample.Steel-to-Steel values are obtained for each batch of testing. Ifmultiple days are involved in the testing, the values are checked daily.The Steel-to-Steel values and the wet test sample values are an averageof 5 replicates at a given load.

Caliper values for a fibrous structure and/or sanitary tissue productare obtained by subtracting the average Steel-to-Steel crosshead trapvalue for a given load from the wet test sample crosshead trap value fora given load (for example at each trap point). For example, the calipervalues from five individual replicates at a given load on each wet testsample are averaged and used to obtain the Wet Compression Value at agiven load. Wet Compression Values are reported in millimeters (mm).

Charge Density Test Method

If one has identified or knows the soil adsorbing agent in and/or on anarticle of manufacture, then the charge density of the soil adsorbingagent can be determined by using a Mutek PCD-04 Particle Charge Detectoravailable from BTG, or equivalent instrument. The following guidelinesprovided by BTG are used. Clearly, manufacturers of articles ofmanufacture comprising soil adsorbing agents know what soil adsorbingagent(s) are being included in their articles of manufacture. Therefore,such manufacturers and/or suppliers of the soil adsorbing agents used inthe articles of manufacture can determine the charge density of the soiladsorbing agent.

1. Start with a 0.1% solution (0.1 g soil adsorbing agent +99.9 gdeionized water). Preparation of dilute aqueous solutions in deionizedwater from inverse or dewatered inverse emulsions are performed asinstructed by the supplier of the emulsions and is well known to one ofordinary skill in the art. Depending on the titrant consumption increaseor decrease soil adsorbing agent content. Solution pH is adjusted priorto final dilution as charge density of many additives is dependent uponsolution pH. A pH of 4.5 is used here for cationic polymers and between6-7 for anionic polymers. No pH adjustment was necessary for the anionicpolymers included in this study.

2. Place 20 mL of sample in the PCD measuring cell and insert piston.

3. Put the measuring cell with piston and sample in the PCD, theelectrodes are facing the rear. Slide the cell along the guide until ittouches the rear.

4. Pull piston upwards and turn it counter-clock-wise to lock the pistonin place.

5. Switch on the motor. The streaming potential is shown on the touchpanel. Wait 2 minutes until the signal is stable.

6. Use an oppositely charged titrant (for example for a cationic samplehaving a positive streaming potential: use an anionic titrant). Titrantsare available from BTG consisting of 0.001N PVSK or 0.001N PolyDADMAC.

7. An automatic titrator available from BTG is utilized. After selectingthe proper titrant, set the titrator to rinse the tubing by dispensing10 mL insuring that all air bubbles have been purged.

8. Place tubing tip below the surface of the sample and start titration.The automatic titrator is set to stop automatically when the potentialreaches 0 mV.

9. Record consumption of titrant, ideally, the consumption of titrantshould be 0.2 mL to 10 mL; otherwise decrease or increase soil adsorbingagent content.

10. Repeat titration of a second 20 mL aliquot of the soil adsorbingagent sample.

11. Calculate charge demand (solution) or charge demand (solids);

${{Charge}\mspace{14mu} {demand}\mspace{14mu} \left( {{eq}\text{/}L} \right)} = \frac{V\mspace{14mu} {titrant}\mspace{14mu} {used}\mspace{14mu} (L) \times {{Conc}.\mspace{14mu} {of}}\mspace{14mu} {titrant}\mspace{14mu} {in}\mspace{14mu} {Normality}\mspace{14mu} \left( {{eq}\text{/}L} \right)}{{Volume}\mspace{14mu} {of}\mspace{14mu} {sample}\mspace{14mu} {titrated}\mspace{14mu} (L)}$${{Charge}\mspace{14mu} {demand}\mspace{14mu} \left( {{eq}\text{/}g} \right)} = \frac{V\mspace{14mu} {titrant}\mspace{14mu} {used}\mspace{14mu} (L) \times {{Conc}.\mspace{14mu} {of}}\mspace{14mu} {titrant}\mspace{14mu} {in}\mspace{14mu} {Normality}\mspace{14mu} \left( {{eq}\text{/}L} \right)}{{{Wt}.\mspace{14mu} {solids}}\mspace{14mu} {of}\mspace{14mu} {the}\mspace{14mu} {sample}\mspace{14mu} {or}\mspace{14mu} {its}\mspace{14mu} {active}\mspace{14mu} {substance}\mspace{14mu} (g)}$

The charge density (charge demand) of a soil adsorbing agent is reportedin meq/g units.

UL Viscosity Test Method 1) Reagents and Equipment

-   -   a) NaC1,    -   b) Deionized water,    -   c) 9 moles Ethoxylated Nonyl Phenol (for example SYNPERONIC NP9        from ICI surfactant),    -   d) Mechanical stirrer fitted with a stainless steel shaft        equipped at the end with about 2 cm radius propeller-type        blades,    -   e) High tall 600 ml beaker,    -   f) Disposable syringes (5 ml, 2 ml and 10 ml)    -   g) Balance with an accuracy of 0.001 g,    -   h) Thermometer,    -   i) 200 μm stainless steel screen.        2) Preparation of an initial 0.5% polymer solution in water    -   a) Obtain a clean 600 ml beaker and fill it with 100 g of        deionized water,    -   b) Start stirring with the mechanical stirrer at 500 rpm to        create a vortex,    -   c) Calculate the weight of pure emulsion (W₀) required to obtain        0.5 g of polymer,

W ₀=50/C

-   -    C is the percentage of active matter in the emulsion    -   d) Withdraw approximately the weight (W₀) of emulsion into a        plastic syringe,    -   e) Weigh accurately the syringe and record the weight filled        (W_(F)),    -   f) Disperse rapidly the contents of the syringe into the vortex        of the beaker,    -   g) Let stir 30 minutes,    -   h) Weigh the empty syringe and record the weight empty (W_(E)),    -   i) Calculate W=W_(F)−W_(E).        3) Preparation of a 0.1% solution of polymer in 1 M NaCl    -   a) Remove the beaker from the stirrer let the shaft and the        blade, drain completely over the beaker,    -   b) Place the beaker on the balance and weigh in accurately:        -   i) 0.2 g of ethoxylated nonyl phenol        -   ii) (Q_(E)) g of deionized water, where            Q_(E)=W×(9.7949×C−1)−100.2,    -   c) Let it stir again for 5 minutes at 500 rpm,    -   d) Then add the salt Q_(s) in g: let if stir for 5 minutes,        where Q_(s)=0.585×W×C,    -   e) Resulting in a 0.1% solution of polymer in 1 M NaCl,    -   f) The polymer solution is now ready for measurement after        filtration through a 200 μm screen.        4) In the Case of a High Molecular Weight Emulsion (UL Viscosity        greater than 7cP)    -   a) Prepare the solution at 0.5% as in step 2.    -   b) Remove the beaker from the stirrer let the shaft and the        blade drain completely over the beaker,    -   c) Place the beaker on the balance and weight accurately:        -   i) 0.2 g of ethoxylated nonyl phenol,        -   ii) (Q_(E)) g of deionized water where            Q_(E)=W×(9.7949×C−1)−100.2,    -   d) Let it stir again for 5 minutes at 850 rpm,    -   e) Then add the salt Q_(s) in g; let it stir for 5 minutes at        850 rpm, where Q_(s)=0.585×W×C    -   f) Resulting in a 0.1% solution of polymer in 1 M NaCl,    -   g) The polymer solution is now ready for viscosity measurement        after filtration through a 200 μm screen.

5) Viscosity Measurement of Polymer Solution

-   -   The viscosity is determined by means of a Brookfield viscometer        model LVT with the UL adapter and a spindle speed of 60 rpm    -   a) 16 ml of the solution are placed in the cup, and the        temperature is adjusted to 23-25° C. the cup is then attached to        the viscometer.    -   b) Let the spindle turn at 60 rpm until the reading is stable on        the dial (about 30 seconds);    -   c) Read the value indicated on the dial:

Viscosity (in cP)=(reading−0.4)×0.1

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

Every document cited herein, including any cross referenced or relatedpatent or application, is hereby incorporated herein by reference in itsentirety unless expressly excluded or otherwise limited. The citation ofany document is not an admission that it is prior art with respect toany invention disclosed or Claimed herein or that it alone, or in anycombination with any other reference or references, teaches, suggests ordiscloses any such invention. Further, to the extent that any meaning ordefinition of a term in this document conflicts with any meaning ordefinition of the same term in a document incorporated by reference, themeaning or definition assigned to that term in this document shallgovern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended Claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. A fibrous structure comprising a wetcompression-enhancing agent such that the fibrous structure exhibits atleast one of the following properties: a. at least one Wet Compressionvalue in a load value range of from 100 g to 300 g during theCompression Portion of the Wet Compression Test Method that isstatistically greater than the corresponding Wet Compression value ofthe same fibrous structure void of the wet compression-enhancing agentas measured according to the Wet Compression Test Method; and b. atleast one Wet Compression value in a load value range of from 50 g to300 g during the Relaxation Portion of the Wet Compression Test Methodthat is statistically greater than the corresponding Wet Compressionvalue of the same fibrous structure void of the wetcompression-enhancing agent as measured according to the Wet CompressionTest Method.
 2. The fibrous structure according to claim 1 wherein thefibrous structure exhibits at least one Wet Compression value in a loadvalue range of from 100 g to 300 g during the Compression Portion of theWet Compression Test Method that is statistically greater than thecorresponding Wet Compression value of the same fibrous structure voidof the wet compression-enhancing agent as measured according to the WetCompression Test Method.
 3. The fibrous structure according to claim 1wherein the fibrous structure exhibits a Wet Compression value ofgreater than 0.446 mm at a load value of 300 g during the CompressionPortion of the Wet Compression Test Method as measured according to theWet Compression Test Method.
 4. The fibrous structure according to claim1 wherein the fibrous structure exhibits a Wet Compression value ofgreater than 0.543 mm at a load value of 200 g during the CompressionPortion of the Wet Compression Test Method as measured according to theWet Compression Test Method.
 5. The fibrous structure according to claim1 wherein the fibrous structure exhibits a Wet Compression value ofgreater than 0.622 mm at a load value of 150 g during the CompressionPortion of the Wet Compression Test Method as measured according to theWet Compression Test Method.
 6. The fibrous structure according to claim1 wherein the fibrous structure exhibits a Wet Compression value ofgreater than 0.676 mm at a load value of 125 g during the CompressionPortion of the Wet Compression Test Method as measured according to theWet Compression Test Method.
 7. The fibrous structure according to claim1 wherein the fibrous structure exhibits a Wet Compression value ofgreater than 0.742 mm at a load value of 100 g during the CompressionPortion of the Wet Compression Test Method as measured according to theWet Compression Test Method.
 8. The fibrous structure according to claim1 wherein the fibrous structure exhibits a Wet Compression value ofgreater than 0.824 mm at a load value of 75 g during the CompressionPortion of the Wet Compression Test Method as measured according to theWet Compression Test Method.
 9. The fibrous structure according to claim1 wherein the fibrous structure exhibits a Wet Compression value ofgreater than 0.923 mm at a load value of 50 g during the CompressionPortion of the Wet Compression Test Method as measured according to theWet Compression Test Method.
 10. The fibrous structure according toclaim 1 wherein the fibrous structure exhibits at least one WetCompression value in a load value range of from 50 g to 300 g during theRelaxation Portion of the Wet Compression Test Method that is greaterthan the corresponding Wet Compression value of the same fibrousstructure void of the wet compression-enhancing agent as measuredaccording to the Wet Compression Test Method.
 11. The fibrous structureaccording to claim 1 wherein the fibrous structure exhibits a WetCompression value of greater than 0.444 mm at a load value of 300 gduring the Relaxation Portion of the Wet Compression Test Method asmeasured according to the Wet Compression Test Method.
 12. The fibrousstructure according to claim 1 wherein the fibrous structure exhibits aWet Compression value of greater than 0.452 mm at a load value of 200 gduring the Relaxation Portion of the Wet Compression Test Method asmeasured according to the Wet Compression Test Method.
 13. The fibrousstructure according to claim 1 wherein the wet compression-enhancingagent comprises a polymer.
 14. The fibrous structure according to claim13 wherein the polymer comprises a water-soluble polymer.
 15. Thefibrous structure according to claim 13 wherein the polymer comprises apolyacrylamide.
 16. The fibrous structure according to claim 1 whereinthe fibrous structure comprises a plurality of pulp fibers.
 17. Thefibrous structure according to claim 1 wherein the fibrous structurecomprises a sanitary tissue product.
 18. The fibrous structure accordingto claim 17 wherein the sanitary tissue product comprises a paper towel.19. The fibrous structure according to claim 1 wherein the fibrousstructure exhibits a Moisture content of less than 30% by weight of thefibrous structure.
 20. The fibrous structure according to claim 1wherein the wet compression-enhancing agent is retained by the fibrousstructure during normal use when saturated with distilled water.